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A fearsome carnivorous dinosaur known for eating its own kind
probably wasn't holding onto its meal as it ate: Its arms were
far too short and stubby, a new fossil find suggests.

Majungasaurus crenatissimus was a 21-foot-long (6.4
meters) predator that was "pretty much the top dog" in what is
now Madagascar 66 million years ago, at the end of the Cretaceous
Period, said Stony Brook University graduate student Sara Burch.
Burch analyzed a recently discovered, nearly complete forelimb of
this ancient animal, the first ever found preserved. In contrast
to the dinosaur's
bulky body, Burch found that its arms weren't even a foot
(0.3 meters) long.

"When you get to the lower arm and the hand, it's really weird,"
Burch told LiveScience. "The lower
arm is very short but thick, and the bones are pretty robust.
So it's not necessarily a thin, wimpy arm, it's just very, very
short."

The fingers of Majungasaurus were so stumpy, in fact,
that the researchers aren't sure they were separated; the hands
may have been more like paddles than like
human hands.

"Even if they were separate, they'd be very short," Burch said.
"Imagine if your hand just had the first knuckles sticking out."

Though many
Majungasaurus fossils have been found, the dinosaur's
forelimb is rarely preserved in the fossil record. Burch was able
to unravel the mysteries of this body part thanks to a nearly
complete Majungasaurus skeleton unearthed in Madagascar
in 2005. She also cataloged other partial Majungasaurus
arm bones from Madagascar.

The researchers don't know what Majungasaurus used its
stubby arms for, though the unusual shape suggests they did have
a specific purpose, Burch said. Whatever it was, it certainly
wasn't for grasping prey, she said.

The forelimb find helps researchers understand the huge diversity
of limbs of theropod dinosaurs like Majungasaurus, Burch
said. Because the dinosaurs walked on their back two legs, their
front limbs were free to evolve for a multitude of tasks. Last
year, researchers even found a
one-fingered dinosaur in Mongolia.

"Majungasaurus really typifies how bizarre, how crazy
they can really go and still have a forelimb," Burch said.